[Pkg-xen-changes] [xen] 04/10: x86emul: only emulate software interrupt injection for real mode

[Bastian Blank]

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waldi pushed a commit to branch develop
in repository xen.

commit a22de27132bab557dcee6e5726d0145364cafcc9
Author: Jan Beulich <jbeulich at suse.com>
Date:   Tue Sep 23 14:40:51 2014 +0200

    x86emul: only emulate software interrupt injection for real mode
    
    Protected mode emulation currently lacks proper privilege checking of
    the referenced IDT entry, and there's currently no legitimate way for
    any of the respective instructions to reach the emulator when the guest
    is in protected mode.
    
    This is XSA-106.
    
    Reported-by: Andrei LUTAS <vlutas at bitdefender.com>
    Signed-off-by: Jan Beulich <jbeulich at suse.com>
    Acked-by: Keir Fraser <keir at xen.org>
    master commit: 346d4545569928b652c40c7815c1732676f8587c
    master date: 2014-09-23 14:33:50 +0200
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c
index 4810e68..5fbe024 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2634,6 +2634,7 @@ x86_emulate(
     case 0xcd: /* int imm8 */
         src.val = insn_fetch_type(uint8_t);
     swint:
+        fail_if(!in_realmode(ctxt, ops)); /* XSA-106 */
         fail_if(ops->inject_sw_interrupt == NULL);
         rc = ops->inject_sw_interrupt(src.val, _regs.eip - ctxt->regs->eip,
                                       ctxt) ? : X86EMUL_EXCEPTION;

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